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US Robotics

flfmdll asked
Medium Priority
Last Modified: 2013-12-27
When I first turn on my external sportster 33.6 modem, the TR and CS lights flash and just keep flashing. It happens about once every second or two. It was working fine until last night.

Does this mean the modem is fried?
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Connect to the COM port that your modem is attached to, via HyperTerminal. Then write AT&F1. IF that does not work try ATZ3.


I did try using the dip switch in the back to reset to factory defaults. If I did it right, that had no effect. I'll give this a try and get back with you. Thanks.

Something to consider:
Resetting the dip switches will probably then cause the modem to be unrecognized by the computer.
If it won't respond using the default switch settings, go back to the last settings that worked and try the AT&F1 command.


Ralph, just so you know, I only reset it via the dip switch after the lights started flashing. Also, the lights the flash whether or not it is connected to the computer (RS232 cable).

Check your documentation for the modem.  Perhaps the flashing LEDs are indicating some type of error code.


I tried looking at the documentation. I don't see anything about flashing lights that does NOT relate to data being transferred. I know there is no data being transferred.

By the way, the modem is at home. I'm at work. So I can't try the software reset until I get home.

But thanks,

Let us know what you find........

There is a high probability that the timed flashing of the modem lights indicates a failure code... or at the very least a modem failure that in-turn creates a very confused modem.
The TR light indicates, in a working modem, Data terminal ready..that is..the computer has set this handshake line to indicate it is ready for a data transfer.
The CR light is the Clear to send handshake signal.

I tied, in vain, to search for Modem light error codes for the USR. If your modem is still under warrenty I would suggest contacting the USR support hotline(847)982-5151.

Good Luck,

John C. Cook
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